This paper introduces a novel user interface that integrates search and browsing of very large category hierarchies with their associated text collections. A key component is the separate but simultaneous display of the representations of the categories and the retrieved documents. Another key component is the display ofmultiple selected categories simultaneously, complete with their hierarchical context. The prototype implementation uses animation and a three-dimensional graphical workspace to accommodate the category hierarchy and to store intermediate search results. Query specification in this 3D environment is accomplished via a novel method for painting Boolean queries over a combination of category labels and free text. Examples are shown on a collection of medical text.

In recent years, a number of models of lexical access based on attractor networks have appeared. These models reproduce a number of effects seen in psycholinguistic experiments, but all suffer from unrealistic representations of lexical semantics. In an effort to improve this situation we are looking at techniques developed in the information retrieval literature that use the statistics found in large corpora to automatically produce vector representations for large numbers of words. This paper concentrates on the problem of transforming the real-valued cooccurrence vectors produced by these statistical techniques into the binary- or bipolar-valued vectors required by attractor network models, while maintaining the important inter-vector distance relationships. We describe an algorithm we call discrete multidimensional scaling which accomplishes this, and present the results of a set of experiments using this algorithm. Introduction Our goal is to develop a connectionist model of lex...